The most obvious theme in The Time Machine is that of a continuing class struggle, even 800,000 years in the future.  As the Time Traveler overlooks the future Earth he notices that the individual family has disappeared and presumes this society to be a form of communism.  This theory is disproved when our hero is introduced to the Morlocks, but we can then begin to see obvious distinctions between what we believe are the Haves and the Have-nots.  Even in the names of the two species we can notice discrepancies.  The word Eloi itself sounds like the word 'elite,' describing a rich, elite being, while Morlocks is a seemingly perfect word to describe a brutish, ape-like creature.  Everything about these two beings points toward the Time Traveler's theory that he is at the apex of civilization, where the two major classes of society have become so set in their positions that there is no possibility of climbing the proverbial social ladder.  As we later find out, there are two distinct classes, set in their ways to the point where there is no social interchange, but it is not the Eloi who rule the Morlocks.  However, Morlocks simply use the Eloi as cattle, providing them with clothes and shelter as a farmer would provide for his herd.  The Time Traveler notices early on that there are no weak and enfeebled to be seen amongst the Eloi and he later determines that the Morlocks feed off their above ground cousins.  The Morlocks seem to hunt their food at night since their bodies have adapted to living in the dark depths of the Earth.  This would explain Weena's extreme fear of dark places and also why the Eloi sleep in large groups.